2002 Fiscal Year Final Research Report Summary
Stucy on interaction between electromagnetic wave and rocket exhaust plume
| Project/Area Number |
11450379
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Aerospace engineering
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| Research Institution | The Institute of Space and Astronautical Science |
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Principal Investigator |
OGAWA Hiroyuki ISAS, Space Systems, Associate Professor, システム研究系, 助教授 (60311172)
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| Co-Investigator(Kenkyū-buntansha) |
KOBAYASI Yasunori ISAS, CAST, Professor, 次世代探査機研究センター, 教授 (10132995)
HIRAKI Koju ISAS, Space Systems, Research Associate, システム研究系, 助手 (40249933)
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| Project Period (FY) |
1999 – 2002
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| Keywords | Rocket / Plasma / Electromagnetic wave / CFD / CEM / Reaction |
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| Research Abstract |
We estimated microwave attenuations by a solid rocket motor plumes, assuming that the attenuation is caused by (I)Aluminum/Alumina particles, and (2)free electrons. The expressions and values of the attenuations show that the microwave attenuation observed in real rocket motors is caused by free electorons.
We analyzed the plume of the H-IIA SRB-A solid rocket motor plume numerically. The numerical model includes a chemical reaction model of the plume gas. The numerical result shows that the chemical reactions are frozen and the mole fraction of electron is constant through the nozzle ; the electron number density is calculated from the pressure and temperature of the gas. The electron mole fraction is strongly depends on the amount of impurity, such as the sodium, in the motor grain
We analyzed microwave propagation in the weakly-ionized plume gas using a two dimensional GEM (Computational Electro Magnetics) model. Results show that (1)the effect of diffraction and refraction of microwave cannot be neglected, (2)the microwave attenuation depends weakly on the microwave frequency, (3)the microwave attenuation is proportional to electron number density, and (4)the microwave attenuation is in inverse proportion to the electron collision frequency.
We conducted a microwave attenuation measurement in the ground firing tests. The theoretical results agrees quantitatively with the experimental result. The electron mole fraction estimated from the experimental result is I order less than that of the theoretical result ; the cause of it is considered the impurities were less than the assumed amount. No modulation of microwave is observed in the received microwave which propagates through the motor plume.
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